Sound is propagated via air, but common wireless earphones or hearing aids, which propagate the sound into the ear via air, often cannot eliminate external background audio source. Thus, an oscillator using bone conduction or skin conduction is accordingly developed.
TW patent no. 463517 discloses a transceiving device using a skeleton conduction based loud speaker, which device is provided with a skeleton conduction based loud speaker part, a microphone part, and a receiving part for a driving circuit, and which device can be connected to a telephone or a wireless transceiver. The abovementioned skeleton conduction based loud speaker part is formed such that it can be attached on any position of the face when the abovementioned microphone part is put aside the mouth. However, the configuration of being attached on any position of the face does not necessarily have the skeleton conduction effect.
Another conventional general touching type of indirect sound wave bone conduction device put on the neck can eliminate some background sound, but the sound quality transmitted therefrom is not clear because of touching the throat. Because it is clipped on the neck, it is likely to slide, meanwhile it is inconvenient and not aesthetically pleasing. And the audio signal of the conventional general touching type of indirect bone conduction device put on the neck will be decayed and less clear than that of a local call.
Another conventional eyeglasses type of bone conduction hearing aid will put an oscillator at the ear tail of a frame for glasses. It can eliminate the background sound, but it is used only for hearing and unable to generate sound. Further, the brace for glasses will loose and unable to attach closely to the ear bone because of usage for a long time, thereby making the effect of hearing aid significantly reduced. In recent years, mobile devices such as mobile phones are popular, and wireless Bluetooth communication devices are very prevalent, such that the problems of hearing and speaking when these mobile devices are in use can be dissolved. Its disadvantages are in that the external background sound can not be removed, it is very uncomfortable for putting on the ear for a long time, the heavy brace for glasses is not aesthetically pleasing, the portion after the ear will sweat and lose the function of the hearing aid, as well as it will fall off easily while taking exercise. Meanwhile, if such eyeglasses type of bone conduction hearing aid uses left and right braces for glasses, then some elements, such as batteries, microphones, etc., can not be shared, it makes the user have to pay approximately twice cost and does not meet economic effect.